Not applicable.
(1) Field of the Invention
The present invention pertains to a tether retraction device which nests or holds together a plurality of individual lines in a multi-line towed array allowing for safe and reliable storage, deployment, and operation.
(2) Description of the Prior Art
Tow lines are used in a variety of different applications. For example, U.S. Pat. No. 2,956,532 to James et al. illustrates a seaplane towing line and U.S. Pat. No. 3,159,806 to Piasecki illustrates a high speed tow sonar system including a paravane with a reel for letting in or letting out the tow line for a satellite carrier.
U.S. Pat. No. 3,298,347 to Swain et al. illustrates a submersible towing apparatus with a reversibly drivable reel. U.S. Pat. No. 4,407,460 to Khudaverdian illustrates a tow rope for a water skier having a spring loaded reel.
U.S. Pat. No. 5,119,751 to Wood illustrates a vertical stabilizer installed towed array handling system in which a vertical stabilizer is provided with a chamber in which is rotatably mounted a reel for rotation about an athwartship axis. One of the side elements of the reel has an engageable surface adjacent its periphery. A drive motor in the stabilizer is engaged with the engageable surface of the one side element to effect rotation of the reel. An elongated cable is coiled about the hub of the reel and extends outwardly of a passage extending to the aft end of the stabilizer. A mechanism inside the vertical stabilizer guides the cable between the passage and the storage space to facilitate coiling of the cable onto the reel and for deploying the cable therefrom. A brake mechanism is used to prevent the reel against rotation to prevent further either deploying or coiling of the cable.
U.S. Pat. No. 5,263,431 to Wood illustrates a combination winch and stowage reel assembly for arrays towed by submarines. The assembly comprises a hub, a slip ring mounted in the hub and in communication with a receiver in the submarine, a reel rotatably mounted on the hub, the reel having gear teeth on a periphery thereof, a tow cable fixed to the reel and adapted to have attached to a free end thereof an array to be towed behind the submarine, the tow cable being in communication with the slip ring to form a communication path including the array, the tow cable, the slip ring, and the receiver, a drive gear engaged with the reel gear teeth, and a motor for turning the drive gear, thereby to turn the reel on the hub to pay out and take up the cable.
A significant problem in the design of a multi-line towed array is to provide a mechanism for reliably deploying and retrieving a system of lines while still providing a system which separates the lines during use to a pre-determined three-dimensional configuration. Often, a multi-line array is deployed and retrieved from a stowage tube (a long tube into which the array is pulled). Experimentation has shown that if the lines move independently of each other during deployment and retrieval, system performance can be compromised. The individual lines must be held together or nested to ensure proper deployment and retrieval performance. The nesting device must operate under the following constraints: (a) allow deployment and retrieval of the multi-line array and proper operation of the system; (b) operate in a seawater environment with an operating pressure of 1000 psi and a survival pressure of 2500 psi; (c) maintain performance for a minimum of one year without maintenance in a submarine environment; (d) operate automatically with neither power nor outside intervention; (e) be compatible with packaging in a 1 inch diameter and a maximum rigid length of six inches; and (f) provide a maximal retraction force in the nested position and a minimum retraction force at the fully extended position.
Currently, there are no existing apparatus or methods to nest the individual lines in a multi-line array.
Accordingly, it is an object of the present invention to provide a tether retraction device which holds or nests individual lines of a multi-line array together during deployment and retrieval.
It is a further object of the present invention to provide a tether retraction device as above which requires no operator activation or intervention.
It is another object of the present invention to provide a tether retraction device as above which provides maximal retraction forces in the nested position and minimal retraction forces at the fully extended position.
It is yet another object of the present invention to provide a tether retraction device as above which has no impact on the performance of a towed array.
The foregoing objects are attained by the tether retraction device of the present invention.
In accordance with the present invention, a tether retraction device for use with a multi-line towed array is provided. The present invention relates to a tether retraction device having particular utility with multi-line towed arrays. A system for retrieving and deploying a multi-line towed array having a plurality of array lines has at least one tether joinable between two of the plurality of array lines. A tether retraction device is incorporated into at least one of the array lines for retracting the tether. The tether retraction device has a tether take-up spool, and a spring driven drive means which causes the tether to wind onto the take-up spool when the array is towed at slow speeds and allows deployment of the tether from the take-up spool when tension in the tether caused by tow forces exceeds the spring force applied by the spring driven drive means. In further detail the invention provides that through a series of take up spools the spring driven drive provides a maximum retraction force in the retracted position and a minimum retraction force in the deployed position.
Other details of the tether retraction device of the present invention, as well as other objects and advantages attendant thereto, are set forth in the following detailed description and the accompanying drawings in which like reference numerals depict like elements.